High-tension spark ignition magneto



Dec. 4, 1945; P. TATLOW ETAL 2,390,338

HIGH TENS IORSPARK IGNITION MAGNETO Filed May 'r, 1943 4 Sheets-Sheet 1 7 1 Tailor? ,ZTJHaZbeffi Dec. 4, 1945. P. TATLOW. EI'AL 2,390,338

HIGH TENSION SPARK IGNITION MAGNETO Filed May '7, 1943 4 Sheets-Sheet 2 Fig.2

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1945. P. TATLOW ETAL 2,390,338

HIGH TENSION SPARK IGNITION MAGNETO Filed May '7, 1943 4 Sheets-Sheet 4 Invezaior; Tcz/toJ/z v I JHZLZQEZ Patented Dec. 4, 1945 HIGH-TENSION SPARK IGNITION MAGNETO Percy Tatlow and Ivan Jack Hulbert, Willesden Junction, London, England, assignors to Rotax Limited, Willesden Junction, London, England Application May 7, 1943, Serial No. 486,094 In Great Britain May 21, 1942 4 Claims.

This invention has for its object to provide an improved high tension spark ignition magneto for use on multi-cylinder internal combustion engines.

The invention comprises the combination of a hollow metal body having two main coaxial parts arranged end to end, one of the said parts being adapted to house the spark generator and the other the distributor, two coaxial stationary distributor parts having a gap between them and carrying the input electrodes, a group of stationary distributor parts mounted in the said gap and carrying the output electrodes, and a rotary distributor part on one end of the spark-generator spindle and carrying connecting electrodes.

The invention also comprises a magneto as specified in the preceding paragraph, in which the spark generator has in combination, a rotor spindle, bearings carrying the spindle, and an interrupter cam mounted on the spindle at the inner side of one of the bearings, the rotary dis- .tributor part being mounted on the end of the spindle which extends beyond this bearing.

In the accompanying sheets of explanatory drawings Figures 1 and 2 are sectional side elevations taken at right angles to each other, and Figures 3 and 4 are part sectional opposite end elevations of a magneto constructed in accordance with the invention.

In carrying the invention into efiect as shown, we employ a hollow metal body comprising two coaxial main parts a, b, having adjacent open ends interconnected by screws as c. The body part a houses the spark generator and the body part b houses the distributor. Situated coaxially within the body part a is a hollow cylindrical portion d which is formed integrally with an annular disc-like member e having its outer marginal portion secured between the adjacent ends of the body parts a, b, the said cylindrical portion being adapted to accommodate the generator-rotor f. A bearing 9 for one end of the rotor spindle h is mounted in a housing i, secured to the inner end of the cylindrical portion d, and a bearing for the other end of the spindle is provided in a removable cover k on the outer end of the said cylindrical portion. Two or more casings m each containing a pair of stationary generating (primary and secondary) windings n, on a core p are mounted on the cylindrical portion d in the body part a. Permanent magnets q and appropriate pole pieces 1- may also be mounted in the body part a, in which case the if desired the permanent magnets may be mounted on the rotor. The interrupter cam s is mounted on the spindle it close to the inner side of the bearing and the other parts of the interrupter with its associated condenser (some of which parts are shown and indicated as a whole by t) are carried by a flange u on the inner end of the bearing housing 1'.

In the distributor we employ an annular member 1; made of insulating material and shaped to form a trough for accommodating high-tension cables. This member 22 is fixedly mounted. in the body part b by screws as 10 so that it lies closely adjacent to the spark generator. Moreover it is provided at appropriate positions with laterally projecting bosses as :c which carry portions y of the input electrodes, these electrode portions being arranged parallel with each other, and being adapted at one end to make contact through the medium of spring-loaded plungers z with terminal pieces 2 connected to the discharge ends of the high tension generator winding 0. The outer end of the body part b is provided with a removable cover 3, and on the inner surface of this cover is secured another distributor part 4, this part serving to carry in radial relationship other portions 1 of the input electrodes. Near its periphery the distributor part 4 is formed with socket-like bosses 5 which extend from the inner face of this part and accommodate in spigot-like manner the adjacent ends of the bosses at on the first described distributor part 11. Preferably and as shown the other ends of the bosses a: are

of socket-like form and accommodate in spigotlike manner complementary bosses 6 on the adjacent sides of the casings m containing the generating windings. At the ends remote from the spark generator the portions 1/ of the input electrodes make contact with the outer ends of the other electrode portions 3 through the medium of spring-loaded plungers l. The inner ends of the electrode portions 31 terminate in two or more exposed metal rings 1 which are carried by the distributor part 4 in coaxial relationship with the generator spindle h, and which are of different diameters and situated in difierent planes.

The two distributor parts 12, 4 above described are spaced apart axially, and between them is fixedly mounted a group of four (or any other desired number) of insulating blocks 8 carrying the output electrodes 9, the latter being arranged to occupy two separate planes; The blocks 8 are secured to the body part b by screws as l0. Also the blocks 8 are arranged around the axis 01' the rotor f is provided with inductor pole pieces, but magneto and are adapted in any convenient m ner for the connection thereto of cables I l which are laid in the trough of the first described distributor part 1) and are connected to terminal blocks as I! mounted in the distributor body. In the example shown the terminal blocks l2 are mounted in hollow bosses l3 formed on the distributor body part b and situated at 90 apart.

The distributor rotor I4 is made of insulating material and is secured on the end of the generator spindle h which extends beyond the spindle bearing 9; This rotor has two radial arms l5 each carrying a connecting electrode IS. The inner end of one of these connecting electrodes l6 co-operates with one of the rings Z, and the inner end of the other co-.operates with the other ring, the outer end of one of the connecting electrodes being arranged to co-operate in succession with the output electrodes 9 in one of the planes above-mentioned, and the other to co-operate with those in the other plane.

The invention above described is especially intended to supply a large number of sparks in each revolution. The advantages obtained by the invention are great compactness as regards axial length, the two main body parts being of approximately equal axial length and diameter, simplicity of construction, and ready accessibility of all parts contained within the body.

It will be understood that in the foregoing we have .described only the main parts which we believe to be essentially novel, and that subordinate details, such as those pertaining to the in-= terrupter construction, lubrication, ventilation and so on may be of any convenient form. Further the invention is not limited to the particular example described as non-essential details may be varied to suit different requirements.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

1. A high tension spark ignition magneto comprising in combination a spark generator, a distributbr, and a hollow metal body, having two main coaxial parts which are arranged end to end, and which respectively house the spark geninput electrodes electrically connected to the spark generator, output electrodes electrically insulated from the input electrodes, connecting electrodes for electrically interconnecting the input and output electrodes, two coaxial and axially spaced stationary parts mounted within'the body and carrying adjacent portions of the input electrodes, a group of stationary members mounted in the space between the said stationary parts and carrying the output electrodes,'and a rotary member mounted on one end of the spark-generator spindle and carrying the connecting electrodes.

2. A high tension spark ignition magneto as claimed in claim 1, in which one of the stationary distributor parts is shaped to form an annular trough for accommodating high tension cables.

' 3. A high tension spark ignition magneto as claimed in claim 1, in which one of the stationary distributor parts is provided with a plurality of bosses carrying portions of the input electrodes, the other stationary distributor part serving to carry the other portions of the input electrodes, and being formed with socket-like parts which accommodate the adjacent ends of the said bosses.

4. A high tension spark ignition magneto as claimed in claim 1, in which the spark generator has in combination, bearings carrying the rotor spindle, and an interrupter cam mounted on the spindle at the inner side of one of the bearings, the rotary distributor part being mounted on the end of the spindle which extends beyond this bearing.

PERCY TA'ILOW. IVAN JACK HULBERT. 

